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An Efficient Markov Chain Based Channel Model for 6G Enabled Massive Internet of Things
( Wei Yang ),( Xiaojun Jing ),( Hai Huang ),( Chunsheng Zhu ),( Qiaojie Jiang ),( Dongliang Xie ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.11
Accelerated by the Internet of Things (IoT), the need for further technical innovations and developments within wireless communications beyond the fifth generation (B5G) networks is up-and-coming in the past few years. High altitude platform station (HAPS) communication is expected to achieve such high levels that, with high data transfer rates and low latency, millions of devices and applications can work seamlessly. The HAPS has emerged as an indispensable component of next-generations of wireless networks, which will therefore play an important role in promoting massive IoT interconnectivity with 6G. The performance of communication and key technology mainly depend on the characteristic of channel, thus we propose an efficient Markov chain based channel model, then analyze the HAPS communication system's uplink capability and swing effect through experiments. According to the simulation results, the efficacy of the proposed scheme is proven to meet the requirements of ubiquitous connectivity in future IoT enabled by 6G.
Control of thermoacoustic instability of liquid-spray flame with porous sound absorber
Hao Zhou,Hao Fang,Dongliang Wei,Zihua Liu,Zhaowen Wang,Hanxiao Meng 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8
A kind of porous sound absorber was studied to control the thermoacoustic oscillation of liquid mist flame, which combined natural fibrous materials and perforated plate. It could optimize the sound absorption characteristics of fibrous materials by adding perforated plate and air cavity. The influences of the interlayer and back cavity depth of two kinds of fibrous materials with the mass of 20, 30, 40 g were investigated experimentally in an impedance tube and applied to control the oscillating ethanol flame. The results showed that the best depth of interlayer and back cavity were 20 cm and 30 cm, respectively. The addition of two kinds of fiber sandwich structures could reduce the amplitude of the sound pressure oscillation in the combustion chamber by 89.2 % and 92.6 %, as well as 88.0 % and 91.2 % in the plenum chamber, meanwhile, restrained the flame heat release fluctuation by 73 %. It was proved that the porous sound absorber could act as a damp in the acoustic transmission path and suppress the sound source.
The Microstructure and Magnetic Properties of Melt-Spun CeFeB Ribbons with Varying Ce Content
Xuchao Wang,Minggang Zhu,Wei Li,Liyun Zheng,Dongliang Zhao,Xiao Du,An Du 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.1
The microstructural and magnetic properties of melt-spun ribbons with thecomposition (CexNd100-x)30FebalCo4Ga0.2B0.92 (where x = 50, 60, 70, 80, and 90)were investigated. The ribbons were examined with Scanning ElectronMicroscopy (SEM), Transmission Electron Microscopy (TEM), and VibratingSample Magnetometry (VSM). It was found that the grain size of the ribbons ison the nanometer scale, and the grain size decreases with decreasing Ce content. The magnetic hysteresis loops showed that the magnetic properties of theribbons gradually deteriorated with increasing Ce content. This is because themagnetic polarization (Js) and magnetocrystalline anisotropy field (HA) ofCe2Fe14B are smaller than those of Nd2Fe14B. Furthermore, from the initialmagnetization curve it was found that increasing the Ce content changes thecoercive force mechanism to the nucleation mechanism. When Ce contentaccounts for 90% of total rare earth metals, the coercive force mechanismmainly appears to be a nucleation mechanism.
Enhanced Strength-Ductility Synergy in Mg-0.5 wt%Ce Alloy by hot Extrusion
Hui Yu,Yu Liu,Ya Liu,Dongliang Wang,Yuling Xu,Binan Jiang,Weili Cheng,Lixin Huang,Weineng Tang,Wei Yu 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.7
The microstructure and mechanical properties of micro-alloyed Mg-0.5 wt%Ce alloys are investigated systemically in this study. It shows that Mg-Ce binary system is very sensitive to extrusion temperature. On the one hand, the high tensile yield strength (TYS) of 343 MPa was obtained by extrusion at 250 °C mainly due to the combined effects of profuse nano-precipitation phase, grain refinement, texture strengthening and high-density dislocation; On the other hand, the excellent elongation of 30% was acquired by extrusion at 300 °C resulting from the elimination of dislocations as well as the modification of texture.
Xiliang Liu,Song Liu,Youkun Fan,Jin Qi,Xin Wang,Wei Bai,Dongliang Chen,Chengdong Xiong,Lifang Zhang 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.104 No.-
The poly(L-lactide-co-e-caprolactone) (PLCL) ureteral stent creeps and loses shape stability, increasingthe risk of stent tube dislocation. The rubbery biodegradable cross-linked PLCL networks were preparedthrough gamma irradiation under vacuum in the presence of trimethylolpropane triacrylate (TMPTA),pentaerythritol tetraacrylate (PET4A), and pentaerythritol triacrylate (PETA). At a standard sterilizationdose of 25 kGy, the gel content and network density of PLCL networks increased with increasingcrosslinking agent content (1, 3, 5, 7 wt%), and crosslinking efficiency decreased in the order ofPETA > PET4A > TMPTA. The average molecular weight (Mc ) between two crosslinks ranged from 2000to 105 g/mol. To perform the beneficial semi-interpenetrated polymer network and characterized bythe principle, the networks were processed in several doses (25, 50, 75, 100, and 125 kGy). In place ofthe Charlesby-Pinner equation, the irradiation cross-linking followed the Chen-Liu-Tang equation. ThePLCL network with 7 wt% PETA had a gel fraction of 83%, tensile strength of 34.7 MPa, and tensile setvalue as low as 5%. Furthermore, degradation in vitro was slowed down. Thus, PLCL networks with appropriateelasticity and flexibility, inherent biodegradability, and excellent biocompatibility can provide apromising alternative method for soft tissue repair engineering, such as ureteral stents.
Microbial transformation of ginsenoside Rg3 to ginsenoside Rh2 by Esteya vermicola CNU 120806.
Hou, Jingang,Xue, Jianjie,Wang, Chunyan,Liu, Lei,Zhang, Dongliang,Wang, Zhen,Li, Wei,Zheng, Yinan,Sung, Changkeun Springer 2012 World journal of microbiology biotechnology Vol.28 No.4
<P>In the present investigation, we successfully employed a cell-free extract of Esteya vermicola CNU 120806 to convert ginsenoside Rg3 to Rh2. Three important factors including pH, temperature and substrate concentration were optimized for the preparation of Rh(2). The optimal condition was obtained as follows: 50C, pH 5.0 and substrate concentration of 3 mg ml(-1). The yield of conversion was up to 90.7%. In order to identify the specificity of the β-glucosidase activity of Esteya vermicola CNU 120806, ginsenoside Re (protopanaxatriol saponins) was treated under the same reaction system. Interestingly, no new metabolite was generated, which elucidated that the enzymatic process only occurred by hydrolysis of the terminal glucopyranosyl moieties at the C-3 carbon of ginsenoside Rg(3). The crude enzyme extract can be used for commercial ginsenoside Rh(2) preparation.</P>